This invention relates to a portable radio device, such as a radio pager, a transceiver, or the like, which serves to rapidly transmit information to a person with such a portable radio device whenever and/or wherever and which is indispensable for an informationalized or an information-centered society in nowadays.
Heretofore, proposals have been made for a wide variety of portable electronic devices, such as an electronic wrist watch, a portable calculator in addition to a portable radio device of the type described. Each of the portable electronic devices includes an integrated circuit (an IC), a large scale integrated circuit (an LSI), or the like which is encased in a housing. Inasmuch as the electronic wrist watch and the portable calculator do not need to receive any radio waves, it may be possible with the electronic wrist watch and the portable calculator to use, as the housing, a metallic housing which is capable of shielding the IC or the LSI from radio waves.
On the other hand, the portable radio device should not make use of a metallic housing and, otherwise, reception of radio waves becomes impossible in consequence of the shielding of the radio waves. Therefore, the housing is formed by a nonconductive material in such a portable radio device. Besides, an antenna has been encased in the nonconductive housing together with the IC or the LSI in order to realize miniaturization of the portable radio device. A recent trend has been directed towards use of an intricate IC or LSI to satisfy various kinds of auxiliary operations required by the person with the portable radio device.
It is mentioned here that such a portable radio device may often be used in an environment in which static electricity readily occurs. For example, the static electricity strongly takes place when the person with the portable radio device walks on a carpet laid on a floor and humidity is between 15% and 35%. Under the circumstances, a body of the person is often electrified or charged at about 12 kilovolts.
It should be noted here that the IC and the LSI are weak against such a high static electricity because they are operated at a low voltage. When the person body is electrified at the static electricity of about 12 kilovolts, such electrification and discharge following the electrification being about malfunction of the portable radio device and may seriously destroy circuit elements of the IC, the LSI, or the like. Thus, the IC and the LSI are susceptible to the influence of the static electricity when they are encased in the nonconductive housing.